Improvement in artificial arms and hands



UNITED STATES PATENT OEErcE.

l THOMAS UREN, OF NEW YORK, N. Y. g

IMPROVEMENT IN ARTIFICIAL ARMS AND HANDS.

Specification forming part of Letters Patent No. 46,159, dated January3l, 1865.

To all whom, t may concern:

Be it known that l, THOMAS UEEN, of the city, county, and State of NewYork, have iuvented certain new and useful Improvements in ArtificialArms and Hands; and I do hereby declare that the following is a full,clear, and exact description thereof, reference being had to theaccompanying drawings, making part of this specification, in which--Figure lis a front elevation of the upper part of a person with anarticial arm and hand applied, and Fig. 2 a back elevation, both figuresrepresenting the mode of attaching the artificial arm; Fig. 3, a sectionof the upper arm, combined with an elevation of the forearm and palm ofthe hand, and representing the forearm as held by the bolt t at rightangles to the upper arm; Fig. 4, a view ofthe back of the hand and aportion of the forearm; Fig. 5, a vertical section of the arm and hand,the forearm and hand taken ina plane at right angles to the plane of thepalm of the hand, and with the fingers distended and the upper armdetached and partly turned, that the plane of the section may representthe mechanism;

and Fig. 6, a plan of the spring.

The same letters indicate like parts in all the figures.

The rst part of my said invention relates to asimple means of connectingan artificial forearm to an artilicial upper arm, so that by a singlecord and its connections the person wearing it can, by the motions ofthe stump of an upper amputation, impart the desired motions to theforearm, and the last part of my said invention relates to animprovedmeans for operating the fingers and thumb of an artiiieial hand.

In the accompanyingdrawings, a represents the upper arm, or that portionof it which eX- tends from the elbow to the shoulder. Itv is madehollow, of wood, papier-mache, leather, or other suitable material. Theupper end is suitably formed to receive the stump of the amputated arm,and to extend up in front and back of the shoulder, as at b b, to whichparts a broad strap, c, or shoulder-plate, made of leather or othersuitable material, is connected by two metallic joints, which I preferto make as represented at d d. To both ends of this strap orshoulder-plate is secured a strap or webbing, e, which extends under thearmpit. To the back ofthe shoulder-plate c, and just below the backjoint d, is secured one end of a strap,f, which extends across the backand over the other shoulder; and one end of another strap, g, isattached to the shoulder-plate c between the two joints d d, extendsacross the back to and under the other armpit, and up in front, where itis connected by a buckle, It, to the first-named strap, f, thetwo beingattached where they cross atthe back, and being also connected byastrap, t, which passes over the shoulder. This strap t' extends beyondthe strap f in front, and is connected by a buckle, j, with acord, lc,which I prefer to make of catgut, which passes under a guide-roller, l,attached to the upper arm, a, and thence it passes through an apertureto the inside ofthe arm a and around a guide-roller, m, to the inside ofthe forearm, where it is attached to the finger-expansion cords, as willbe hereinafter described. The fore or lower arm, n, is also made hollowand of wood or other suitable material, and it is hinged to form theelbowjoint by hinge'pieces 0 o. A cord, p, is attached to the inside ofthe forearm at q, a short distance below the elbow-joint and at the rearpart thereof, and this cord passes over the guide-roller m in the lowerpart of the upper arm, and thence passes out through a hole in the rearpart, and not far from the upper end, and there passes around aguide-pulley, andis then secured by a buckle, s, to a short stra-pprojecting from the strap j' at the back; and by reason of the connections of this cord it results that when the stump of the natural arm ismoved forward, as in the act of lifting the natural arm, a pull is madeon the cord p, which lifts the forearm n toward the face, as by theaction of the contracting muscles of a natural arm, and when the stumpof the natural arm is moved back the tension on this cord is relieved,and the forearm descends by gravity.

It is desirable for many purposes to hold the forearm in a position ator nearly at right angles with the upper arm. To do this by the actionof the stump of the natural arm would be Very fatiguing, particularly inthe case of a short amputation.

without fatigue, I have combined with the two parts of the arm hinged aslidingbolt, t, or stop, which is adapted to slide in a recess in theback part of the forearm n, and near the This bolt has a short handle,

elbow-joint.

To effect this purpose' which projects through a slot to the outersurface, so that it can be reached conveniently to be operated. Une edgeof the said slot is notched, and the opposite edge is provided with astrip of vulcanized india-rubber, or equivalent spring, which pressesagainst the handle of the bolt, and by its tension tends to force itinto the notches formed in the opposite edge of the slot. Tvv'hen thebolt is push ed until its handle is forced into the notch nearest theelbow-joint, the end of the bolt abuts against the lower end of theupper arm', c, and the forearm a is thereby held in a position formingan acute angle with the upper arm, and if the said handle be placed inthe middle notch the forearm will be held in a position at right angleswith the upper arm, and when placed in the notch farthest from the elbowjoint the end of the bolt clears the upper arm and leaves the forearmfree to be moved. I n this way the forearm can be readily fixed in anydesired position, or left free to be operated by the motions of thestump of the natural arm, and as there is a spring-pressure which tendsconstantly to force the handle into the notches, to operate the bolt itis only necessary to draw the handle out of any one notch, and by itpush the bolt lengthwise to the desired position.

lt is best to make the wrist part u separate from the forearm and hand,and fitted to the lower end of the forearm by a flute-joint, so that itcan turn thereon, and -fitted to the upper part of the'hand ru byforming the outer end ofthe said wrist-piece ofa semi-cylindrical shapefitted to a socket of corresponding shape in the upper end of the hand,and a rod, w, inserted and secured in the hand, is hinged to anotherrod, m, so that the axis of this joint shall be about the junction ofthe hand with the wrist-piece, and this latter rod, w, extends throughthe wrist-piece into and through a hole in a crosstbar, y, placed in thelower part of the forearm, and this rod has a short arm, e, projectingfrom it with two cords, a', which extend in opposite directions throughholes in and to the outer surface of the forearm, where they are tied,so that by drawing on these cords and tying them the hand can be turnedand set in any desired position.

The hand is preferably made in one piece as far as the mainknuckle-joints b', and the foreiinger and the little finger areconnected with the hand by rule-joints7 and a fulcrum-pin, d',

passes through, on which the rear endsvof all the llgers e c e c aremounted so as to turn t0 a limited extent, the rear ends of the iingelSbeing so formed as to4 strike against a lOd, ff, parallel with thefulerum-pin d' and above it, which serves as a stop to limit the rangeof motion of the fingers either when opened or closed.

rlhe lingers are each formed with a second knuckle-joint, g', which ispreferably lnade in the form of rule-joint, as represented. The thumb his connected with the hand by a rule or other equivalent joint, i. Ifdesired, it may be made with a second joint, like the fingers, but thisis not deemed to be essential.

Four cords, jj j j', preferably made of catgut, and which I term thefinger-expansion cords, are attached, one to each finger, between thesecond knuckle-joints and the tips, pass over the outer surfaces, whichare best made with guide-grooves for the purpose, and under guidestaplesnear the main knuckles. The four cords pass under a guide-roller, k', inthe hand, and beyond that they are all connected to one cord, lf, andthence continue as a single cord through to the inside of the forearm toand around a guide-roller, m', mounted in the forearm, and then it isattached to the upper side of a spring, a', to be presently described;and the said expansion-cords are also united to the cord 7." beforedescribed, so that the lingers can be opened either by the tension ofthe spring or by the same back movement of the stump of the arm which isrequired for throwing out or straightening the forearm. A fifth cord,s', which is attached to the thumb, back of its fulerum-pin, and which lterm the thumb-expansion cord, passes inside of the hand, under aroller, o', and is then attached to the linger-cords, where they areunited, and to be operated in like manner. The four lingers and thethumb are closed by the tension of the spring a within the forearm. Thisspring is preferably made of coiled wire and held in place by thecrossbar y, which extends through it and across the inside of theforearm and this springis so coiled as to have two arms, q', and one,1", and the arm r is formed by bending the wire at the middle of itslength and then coiling up each end in the form of two helices, and thenextending the two ends and leaving them to project sutliciently to formthe other two arms, g', to the extremities of which cords s2 s2 areattached, which pass through holes to the outside of the forearm, wherethey are connected so that they can be readily tightened or loosened toincrease or decrease the tension of the spring to regulate the grasp ofthe iingers and thumb.

Four cords, t', termed the finger-contracting-cords,77 (one for eachtinger,) are attached to the under side of the lingers, pass to the in-lside of the hand, over the guide-roller 7c', to the front side ot' thearm o" of the spring 11X, t-o which they are all attached, and a fifthcord, o', termed the th umh-contracting cord, is attached to the innerpart of the thumb, and passes around the roller o', and thence as thenger-contracting cords', and like them attached to the arm r of thespring a.

By the means above described the lingers and thumb are closed orcontracted by a spring, the tension of which always tends to close them,and by a force which can be readily regulated, and they are opened orexpanded by pulling on the linger and thumb expanding cords, which iseffected by the same outward movement of the stump ofthe amputated armwhich is used for throwing out the forearm.

From the foregoing it will be seen1 that the fingers and thumb are thussuspended to the spring, which is interposed between the eX- pansion andcontraction cords, and which are connected with it on opposite sides, sothat by tightening the cords which are connected to the arms q, of thespring the tension of the said spring will con tract the lingers andthumb and th us keep the hand closed but by throwing out the arm theexpansion-cords are pulled by their connection with the straps over thebreast, which overcomes the tension of the spring n', and the ngers andthumb are thereby expanded to open the hand.

The outer end of the arm r of the spring n', with which the expansionand contraction cords are connected on opposite sides of it, projects toa sufficient distance outside ot' the forearm, so that bearing the outerend of it on a table or any other surface and drawing the arm back willcanse the fingers and thumb to be operated and the hand to be opened atthe will of the person wearing it.

WVhen this is to be applied to an amputation below the elbow, but whichis not too near the wrist, the spring n and its connections should beplaced lower down toward the wrist to leave the requisite room for thereception of the stump ofthe natural forearm, to which the upper end ofthe forearm will be properly adapted 5 and although I have hereindescribed the adjustability of the several cords as being effected bysimply tying, I wish it to be distinctly understood that I do not limitmyself to the use of such means of adjustment and attachment, havingsimply adopted such mode as being cheap, simple, and convenient; but itwill be obvious that other and equivalent modes of attachment andadjustment may be substituted without changing the principle or mode ofoperation which constitutes my invention.

I claiml. Combining the forearm, which is hinged at the elbow to theupper artificial arm, with a cord attached to the back of the forearmand below the elbow-joint, and which passes over a guide-roller mountedin 'the forearm and near the lower part thereof, and thence through theback of the upper arm, and attached to the strapping at or near theback, substantially as described, thus enabling` me to produce anartificial arm for an upper amputation which, by a single connectionwill enable the person wearing it to move the arm at will, as described.

2. rIhe spring arm or lever which projects to the outside of theforearm, so as to be operated by beariu g against any resisting-obj ect,substantially as described, in combination with the jointed fingers andthe expansion and contraction cords, substantially as and for thepurpose specified.

THOMAS UREN.

Witnesses:

WM. H. BISHOP, ANDREW DE LACY.

